(1) Field of the Technology
The present technology relates to a toner cartridge for use in an image forming apparatus such as a laser beam printer, multifunctional machine or the like, in particular relating to a toner cartridge for storing toner such as a replaceable toner hopper, toner bottle, etc., as well as relating to an image forming apparatus using the cartridge.
(2) Description of the Prior Art
Conventionally, with demands for high quality and high-speed image printing, in the field of the image forming apparatuses such as copiers, facsimile machines and the like that use a dual-component developer, a toner cartridge, processor cartridge or the like is used to automatically supply toner to the developing unit to thereby perform continuous image printing.
In the thus configured image forming apparatus, when toner runs out, it is possible to supply toner in a simple manner by replacing the toner cartridge, process cartridge or the like. Toner cartridges for replacement are often stored in a storage or an empty space in a room, and may be stocked without their position regulated or may be oriented in every possible direction.
Accordingly, when toner cartridges of a type that discharges toner from one end are stacked and positioned vertically with the toner discharge port side down, the toner in the cartridge moves down due to gravity with the lapse of time, hence the toner around the toner discharge port becomes compact. As a result, there is a fear that the toner aggregates or becomes lumps, blocking the toner discharge port.
If the toner cartridge in this condition is newly mounted, toner is unlikely to be dispensed from the toner cartridge, and it could happen that it is determined that no toner remains in the toner cartridge even though a plenty amount of toner is left in the cartridge because no toner is discharged.
To deal with this situation, when a new toner cartridge is mounted to the image forming apparatus, it is requested for the user to mount the toner cartridge after shaking the cartridge several times. However, this has not brought about a complete solution of the above problem.
Particularly, since recent toner is improved in low-temperature fusing performance for the purpose of energy saving, the toner presents low storage stability in exchange and shows a stronger tendency to easily cause toner aggregation when the toner cartridge has been left as it is.
Besides, since recent image forming apparatuses have been demanded to be compact, the toner cartridge and the developing device are also made smaller in size and reduced in their mounting space. Accordingly, if the same amount of toner is stored, the toner needs to be packed in the downsized storing space, hence this further increases the possibility of toner aggregation.
Further, as is often the case, the user or the operator tends to forget to shake the toner cartridge before mounting the toner cartridge that has been preserved in a storage into an image forming apparatus. As a result, there occurs the case that the toner will not be dispensed due to toner aggregation inside the toner cartridge, causing troubles such as insufficient toner concentration in the developer and/or stoppage of the operation of the whole image forming apparatus.
On the other hand, as a conventional technique for preventing toner aggregation that would occur around the toner discharge port of the toner cartridge, a developer feeder has been disclosed (see patent document 1 (Japanese Patent Application Laid-open 2000-214667), in which part of the conveyor spiral of the conveying auger is cut off around the toner discharge port of the toner cartridge so as to enlarge the volume of the hollow space around the toner discharge port to thereby reduce the mechanical or thermal stress acting of the toner that is successively conveyed, on the toner at around the discharge port.
However, even with the toner cartridge of patent document 1, if the toner cartridge is left for long time with its toner discharge port down and resultantly the toner loses its fluidity (has become aggregated in some degree), the toner around the toner discharge port cannot be discharged out at the first action of toner supply after attachment to the image forming apparatus or when the toner conveying screw such as an auger screw or the like starts rotating. As a result, the toner to be discharged loses the place to go, and becomes compressed and packed by the pressure of toner conveying screw, causing the problem that toner conveying screwing is locked.